The present invention is generally directed to devices used in industrial aseptic processing and, more specifically, to a device and method for removing fouling deposit build-up on measurement gauges used in aseptic processing of food products.
The thermal processing system of an aseptic processing and packaging system is made of a series of heaters and coolers connected by a piping network that forms a continuous flow channel for passing processed food products. Measurement devices, such as temperature gauges, are installed at the inlet and outlet of one or more heat exchangers to control the operating properties of the heat exchangers.
Because of the continuous heating and cooling operations during the industrial aseptic processing, insulation build-up, such as fouling deposit, is common on every surface coming in contact with highly fouling-prone fluids, particularly, puddings and gels. This has negative consequences on control and operation of industrial heat exchangers, on the quality of the final product, and on the economics of the industrial process.
While strategies to minimize the fouling effects on heat exchangers are available, their reliability is, among other factors, undermined by the accuracy with which the instantaneous fluid properties, such as temperature, are measured at various points throughout the heating and cooling operations. The main reason for these inaccuracies is the fouling that inevitably accumulates on the temperature and other measurement gauges commonly utilized in the aseptic processing system. These gauges are typically enclosed within a piping structure or other equipment, making them difficult to keep clean. Depending on the extent of the build-up, the instantaneous signal received from the measurement gauge can be in error, in spite of the high resolution of the measurement probe.
Accordingly, there is a need for device and method of removing fouling buildup along the exterior surface of measurement devices used in aseptic processing. Such a device must be easy to manufacture and incorporate into existing thermal processing systems.
The present invention is directed to a device and method for removing build-up on such measurement gauges. The inventive device and method involve a movable scraper that fits around a protective shield of a measurement gauge and removes the build-up on the shield. Movement of the scraper is preferably accomplished by a magnetic coupling between a magnetic core attached to the scraper, which is inside a pipe or other piece of equipment, and solenoids or permanent magnets that are installed on the outside of the pipe.
In one embodiment, the invention is directed to an apparatus for obtaining local fluid properties along a fluid piping system comprising a primary pipe comprising an inlet, an outlet, and at least one sidewall that defines a conduit for passing fluid from the inlet to the outlet. A protective shield is disposed with the conduit. A scraper is disposed about at least a portion of the protective shield for removing fouling deposit or other buildup on the protective shield. The scraper is longitudinally movable along the protective shield between a first position and a second position by an external force. The external force is preferably an electromagnetic force generated, for example, by solenoids positioned outside the primary pipe. A measurement device, such as a temperature sensor, is mounted within the protective shield between the first position and the second position.
In another embodiment, the invention is directed to a method for cleaning a portion of a protective shield containing a measuring device. The method comprises providing a scraper disposed about at least a portion of the protective shield, and applying an external force to the scraper to move the scraper longitudinally along the protective shield between first and second positions to thereby clean the portion of the protective shield over which the scraper moves.
In yet another embodiment, the invention is directed to an apparatus for obtaining local fluid properties along a fluid piping system. The apparatus comprises a primary pipe comprising an inlet, an outlet, and at least one sidewall that defines a conduit for passing fluid from the inlet to the outlet. A generally-tubular protective shield is disposed with the conduit and has an end that is mounted in a hole in the sidewall of the primary pipe. A measurement device is mounted within the protective shield. A wire extends through the protective shield and has a first end connected to the measurement device and a second end outside the primary pipe.
The present invention provides a device and an improved method for obtaining a more accurate instantaneous reading of the measurement gauge and improve control and operation strategies of heat exchanges, with significant economic advantages.